Preparation of hides for the manufacture of leather.



UNITED ST rEs ATEN Fnrc.

OTTO ROHM, OF ESSLINGEN, GERMANY.

To all whom it may concern:

Be it known that I, OTTo RoHM, a subject of the German Emperor, residing at Esslingen, Germany, have invented a certain new and useful Improvement in the Preparation of Hides for the Manufacture of Leather, of which the following is a specification.

For hating hides, that is to say, for removing the lime and fatty matter from the hides after the liming process, dog manure has been used for a long time.

The present invention has for its object, to provide a simpler and more reliable method of removing the lime, together with the fatty matter and the remnant of the hairs. For this purpose I treat the hides with an aqueous extract from the pancreas of animals. The rincipal constituent of the said ancreatic extract is trypsin, the effect of which is materially assisted by the other enzyme of the pancreas, viz. steapsin, which has the property of splitting up fat and'com l'eting the saponification of the fat container in the hides.

Aqueous pancreatic extracts alone have a very eflicient hating action, but'it is advantageous to add salts of ammonia or of alkalies or mixtures of such salts. The favorable effect of these salts on hides becomes apparent chiefly by the fact, that the hides shrink, become thinner and are less liable to become rough, on being placed in ure water after the hating process, which efect is liable to occur, when the hides have a strong alkaline reaction and the water contains a considerable quantity of calcium-bicarbonate.

The details of procedure will appear from the following example: A pancreas weighing about 250 grams is extracted with 1 liter of water, and 10 cubic centimeters of this extract are added to 990 cubic centimeters of a 0.1 per cent. aqueous solution of ammonium chlorid. The solution thus obtained is an excellent bate.

Specification of Letters Patent.

Application filed October 12, 1907.

Patented May 5, 1908.

Serial No. 397,149.

When the hides, which have been limed and have an alkaline reaction, are introduced into the batin li uid, the hides are liable to become roug 1, t rough the preci itation of calcium carbonate, in case tie water employed contains much cal cium-bicarbonate in solution. This defect may occur, whether the hating liquid contains trypsin alone, or together with salts of ammonia or alkali, and it may be avoided by subjecting.

the water intended for the preparation of the hate, to a preliminary treatment, which consists in precipitating the carbonic acid by means 0 a suitable quantity of lime water,

.or in adding to the hating liquid before the introduction of the hides starch-paste or other organic or inorganic materials adapted to envelop the calcium carbonate.

If desired, both remedies, viz. lime Water and starch-paste, may be used at the same time.

What I claim is:

1. The process for hating hides, which consists in treating the hides with an a ueous extract of the ancreas of animals, su stantially as described.

2. The process for hating hides, which consists in treating the hides with an aqueous pancreatic extract containing an ammoniasalt, substantially as described.

' 3. The process for hating hides, which consists in treating the hides with an aqueous pancreatic extract containing a mixture of salts of alkali and ammonia, substantially as described.

In witness whereof I have set my hand hereunto in the presence of two subscribing witnesses.

OTTO RQHM. 

